Holy crap! Thanks op!
From Zamzar:
Storage of User Files
When users upload files to be converted Zamzar stores those files on its servers until such time as those files have been converted to the new file format. As soon as this has been done Zamzar removes the original user files from its servers. The converted files remain in place on the servers for users to download, until such time as they expire, at which point they are deleted. Files stored for download are only accessible by Zamzar and through the clickable link generated for download.